io_lib

MODULE

io_lib

MODULE SUMMARY

IO Library Functions

DESCRIPTION

This module contains functions for converting to and from
strings (lists of characters). They are used for implementing the
functions in the io module. There is no guarantee that the
character lists returned from some of the functions are flat,
they can be deep lists. lists:flatten/1 can be used for
flattening deep lists.

EXPORTS

Returns a character list which represents Term. The
Depth (-1) argument controls the depth of the
structures written. When the specified depth is reached,
everything below this level is replaced by "...". For
example:

Also returns a list of characters which represents
Term, but breaks representations which are longer than
one line into many lines and indents each line sensibly. It
also tries to detect and output lists of printable characters
as strings. Column is the starting column (1),
LineLength the maximum line length (80), and
Depth (-1) the maximum print depth.

Returns a character list which represents Data
formatted in accordance with Format. See
io:fwrite/1,2,3 for a detailed
description of the available formatting options. A fault is
generated if there is an error in the format string or
argument list.

If (and only if) the Unicode translation modifier is used
in the format string (i.e. ~ts or ~tc), the resulting list
may contain characters beyond the ISO-latin-1 character
range (in other words, numbers larger than 255). If so, the
result is not an ordinary Erlang string(), but can well be
used in any context where Unicode data is allowed.

Tries to read String in accordance with the control
sequences in Format. See
io:fread/3 for a detailed
description of the available formatting options. It is
assumed that String contains whole lines. It returns:

{ok, InputList, LeftOverChars}

The string was read. InputList is the list of
successfully matched and read items, and
LeftOverChars are the input characters not used.

{more, RestFormat, Nchars, InputStack}

The string was read, but more input is needed in order
to complete the original format string. RestFormat
is the remaining format string, Nchars the number
of characters scanned, and InputStack is the
reversed list of inputs matched up to that point.

{error, What}

The read operation failed and the parameter What
gives a hint about the error.

This is the re-entrant formatted reader. The continuation of
the first call to the functions must be []. Refer to
Armstrong, Virding, Williams, 'Concurrent Programming in
Erlang', Chapter 13 for a complete description of how the
re-entrant input scheme works.

The function returns:

{done, Result, LeftOverChars}

The input is complete. The result is one of the
following:

{ok, InputList}

The string was read. InputList is the list of
successfully matched and read items, and
LeftOverChars are the remaining characters.

eof

End of file has been encountered.
LeftOverChars are the input characters not
used.

{error, What}

An error occurred and the parameter What gives
a hint about the error.

{more, Continuation}

More data is required to build a term.
Continuation must be passed to fread/3,
when more data becomes available.